1. Field of the Invention
The present invention generally relates to dimmer switches, and more particularly to dimmer switches operated by gestural motions, rather than by physically touching the switch.
2. Description of the Prior Art
Potential problems arise in gestural control dimmer switches where the user inputs commands within a continuous spectrum hand detection field formed along a dimmer panel. Touchless dimming is complicated by the fact that downward hand motion cannot always be ignored, as it is sometimes a desired “dimming” action on behalf of the user. It is therefore important for a touchless dimmer system to recognize when a user is attempting to interact with the system and when a user wishes to be ignored. In a light dimming system based on hand gestures this is extremely important since many users will gesture towards the appropriate dim level, but upon reaching this level will then let their hand relax and fall down to their side. If the hand detection field in a gestural control dimmer switch is arranged vertically and the motion of the falling hand is acted upon, the lights will dim down with every interaction. Thus, a gesture-based system must always know when to ignore certain gestures.
Reacting appropriately to gestural commands presents several problems other than the issue of how to properly determine input. The methods by which dimming input is accepted and then translated to the illumination level of the light also pose problems. For example, assume the last user of a dimmer switch has set the light connected to the switch to an 80% illumination level corresponding to a set location along the dimmer panel. If the next user decides to dim the light, he or she will move his or her hand into the hand detection field and initially position it near one end of the panel, typically near the bottom of the panel, at perhaps 20% of the length from the bottom. The system can potentially react to this initial hand position in several negative ways.
In one scenario the system can be set to immediately respond to the initial hand position. This would result in the light immediately dimming from its previous value of 80% illumination level to a 20% illumination level corresponding to the initial position of the user's hand position along the panel. From here, the user could raise or lower his or her hand to brighten or dim the light, respectively. However, the initial drop in the brightness of the light from 80% to 20% can be jarring and undesirable. This problem can be referred to as “introduction jumping.”
To avoid “introduction jumping,” a gestural control dimmer switch system could be designed not to adjust to the first detected position of the hand. Instead, the system would take the placement of the hand as a new baseline or “home” position and subsequent movement of the user's hand from the new baseline position will brighten or dim the light. For example, if the light is at an 80% illumination level when a user moves his or her hand into the hand detection field, wherever the hand is first placed will be established as a new set point on the panel corresponding to the 80% illumination level. Moving the hand up from this new set point will brighten the light; moving it down will dim it. This avoids the “introduction jump” problem mentioned above, but presents a new problem.
If the last user has dimmed the light to an 80% illumination level, when the next user places his or her hand in the hand detection field at 20% from the bottom of the panel, as indicated above, the physical position of the user's hand at 20% from the bottom of the dimmer panel will be set to correspond to the 80% illumination level of the light. However, the bottom of the panel must still correspond to a 0% illumination level in order to retain the ability to dim the light through a full range of illumination levels. Therefore, all of the dimness values from the 80% illumination level down to a 0% illumination level are compressed into the small range of hand positions corresponding to the physical positions located along the panel between 20% and 0%, such that tiny movements of the hand through the 0% to 20% illumination range would dim or increase the illumination level rapidly with less ability to make fine adjustments. This can be referred to as “over compression.” Conversely, the large range of hand positions from the 20% to the top of the panel corresponds to a small increase in the illumination level from 80% to 100% illumination, requiring large movements of the hand to make small changes in illumination level. This problem can be referred to as “over expansion.”
The present invention overcomes problems of introduction jump, over compression and over expansion in the operation of touchless dimmer switches.